Screw-propeller.



O. P EGGAN. SCREW PROPELLER. APPLICATION FILED APE.6, 190B.

Patented Dec. 29, 1908.

awwantoz Witneooeo OLE P. EGGAN, OF SEATTLE, WASHINGTON.

SCREW-PROPELLER.

' No. ceases.

Specification of Letters Patent.

Patented Dec. 29, 1908.

Application filed April 6, 1908. 7 Serial No. 425,4;84.

' To'all whom it may concern: i

Be it known that I, OLE P. EGGAN, citizen of the United States, residingat Seattle, in the county of King and State of \Vashington, haveinvented new and useful Improvements in Screw-Propellers, of which thefollowing is a specification.

My invention pertains to marine propulsion and more particularly toscrew-propellers; and it has for its general object to provide a screwpropeller. which, in proportion to its size, is possessed of largecapacity both in propellin and backing a vessel, and one of such formthat it will tend to slide oil of any object encountered in the Waterand not be liable to be broken by the same, and which will take firmhold of the water at all times and consequently will not subject itsdriving machinery to sudden shocks and strains.

To the attainment of the foregoing objects my invention consists inapropeller which terminates at its rear end in a point, and whichcomprises a forward, longitudinal socket. designed to receive and befixed on the shaft of a vessel, a longitudinal central body portionreduced. as compared with said socket and exteiiding rearwardlytherefrom, and spiral blades which extend from the socket throughout thelength of the longitudinal central body portion to a point adjacent tothe rear end of said body portion and are gradually increased in widthfrom their forward ends to points near their rear ends; the said spiralblades being relatively arranged to form spiral channels between them.It will be manifest that the peculiar arangement of the blades incombination with the longitudinal central body terminating in a point inrear of the rear ends of the blades, will enable the propeller to slipor slide past any obiect it 'may strike in the water, with the resultthat the liability of the propeller being broken while in service isreduced to a minimum.

'lhe details of the construction constituting the best practicalembodiment of my invention known to me will be fully understood from thefollowing description and claim when the same are read in connectionwith the drawings, accompanying and forming part of this specification,in which:

Figure l is a side elevation of my novel screw propeller taken from oneview point, and Fig. 2 is a side elevation of the propeller taken fromanother view point and better illustrating the channels.

Similar letters designate corresponding parts in both'views of thedrawings, referring to which:

A is the body or longitudinal central portion of my novel propellerwhich is preferabl reduced in size gradually toward its rear en a.

B is a socket which is preferably formed integral with the said body orlongitudinal central portion A and is designed to receive a propellershaft. lhe said socket may be fixed to the shaft through the medium of aset screw b or any other means consonant with the purpose of myinvention.

In addition to the body or longitudinal central portion A my novelpropeller comprises s iral blades C which extend from the soclietthroughout the length of the body A to a point adjacent to the rear endof said body and are gradually increased'75 in width from their forwardends to points near their rear ends, as best shown in Fig. 1. It willalso be noticed by reference to Fig. 2 that the spiral blades arerelatively arranged to form between them spiral channels D. The body Aextends about the proportional distance illustrated in rearof theadjacent rear portions of the blades 0 and has 1s rear terminal taperedas illustrated so as to assist the blades and the propeller as a wholein sliding out of engagement with or slipping past obstructionsencountered in the water.

I prefer to have the blades 0 respectively comprise an inner portion 0integral with the body A and an outer portion (Z, connected by rivets eor other suitable means to the inner portion, this being advantageoussince in the event of an outer portion (i being broken it may be removedand replaced with a new outer portion (Z, and. in that way the period ofusefulness of the propeller as a whole may be materially prolonged.

Having described my invcnticn, what I claim and desire to secure 1);Letters- Patent, is:

A screw propeller comprising a forward socket equipped with means forfixing it on a propeller shaft, a longitudinal central bodyportionformer integral with and extending rcarwardly from said socketand having a rear, tapered end, and spiral blades extending in thedirection of the length of the body portion and increased in width fromtheir forward ends to points near their relatively arranged to formspiral channels 10 rear ends and each having ,an'inner portion betweenthem. integralwith the body portion and an outer In testimony whereof Ihave hereunto port1on attached to the inner portion and setmy hand inpresence of two. subscribing '5' adapted to beremoved and replaced withwitnesses.

.9; new outer portion when necessity'de- OLE P. EGGAN. mends; thesaid'ta ered rear end ,of the Witnesses: .body ortion exten ing in rearof the rear MARTIN J.'LUND, ends 0 theiblades, and the said blades beingHENRY GULLIKsEN,

